Hermetically sealed cases can be used to isolate electronic devices from environmental contamination. To form electrical connections between the interior and the exterior of a hermetically sealed case, a hermetic feedthrough can be used. This hermetic feedthrough maintains the integrity of the hermetic sealed case, while allowing electrical signals to pass through. The sealed case and hermetic feedthrough may have a number of gold surfaces. For example, gold braze joints can be used to seal electrically conductive pins into the feedthrough or to seal the feedthrough into an aperture in the hermetic case. Gold is a relatively inert element and resists many types of chemical corrosion. However, in implanted environments gold can corrode, particularly when subjected to high electrical current densities.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.